I'll answer your questions

iS gerald evil

I don't think so, but I've never actually checked. She does seem kinda creepy though.

will I die alone or whatever

No, it'll be a freak roller coaster accident. Everyone around you will die, too.

What is Gerald made out of?
For that matter, what is goblin's made out of?

Paintings of angels.
Me's made of organic matter.

Gerald, what's the other side like?

Also, what's your favourite color? And do you spell it color or colour?

I asked Gerald for you. She can't speak, but I can roughly translate her meaning. She says the other side is like a dream. You don't have awareness of having a body, but you have an awareness of self. There is nothing. No landscape, no stimulus. There is only silence, a silence that lasts forever, that goes by in an instant.

My favorite (spelled favorite) color is purple... In my region... It's spelled color... Too much personal info has been given out. As a smokescreen, I will now answer half of the questions (rounded down) in the next Q Batch (stands for Question Batch) with LIES.

gerald will you watch kamen rider drive with me it has gay cars

Gerald will watch Kamen Rider Drive with you... but another translation of what she said is "I will open your body and watch your gay car anime from within you" so take that as you will.

After I asked that question, Gerald disappeared.

gerald would you be willing to buy a goblin-finder 3001?

Oh but she left a note saying "No."

goblin's, how trustworthy are Gerald's answers?

I wouldn't trust her at all. She's just a crude drawing given life through use of a clipping mask and classical art. Her shape is wrong.